SQL - 如果其中一個ID具有某個列值，則選擇所有匹配的ID

Question

我不確定如何說出該問題，但它更容易解釋。

如果我有一個表，看起來像這樣：

 
+-------+----------+-------+ 
| User | Result | Level | 
+-------+----------+-------+ 
| 1 | Victory |  1 | 
| 1 | Victory |  2 | 
| 1 | Victory |  3 | 
| 2 | Victory |  1 | 
| 2 | Defeat |  2 | 
| 3 | Defeat |  1 | 
| 4 | Defeat |  1 | 
| 5 | Defeat |  1 | 
+-------+----------+-------+ 

我希望能夠只選擇「用戶即有3級的勝利所以選擇將返回：

 
+-------+----------+-------+ 
| User | Result | Level | 
+-------+----------+-------+ 
| 1 | Victory |  1 | 
| 1 | Victory |  2 | 
| 1 | Victory |  3 | 
+-------+----------+-------+ 

其他人不會因爲他們沒有完成3級而退回。

非常感謝！我希望我解釋清楚。

Answer 1

如果你只是想知道哪些用戶有3級的勝利：

SELECT User FROM my_table WHERE Result = 'Victory' AND Level = 3 

但是，如果（因爲你已經證明），你希望所有這些用戶的結果（與感謝@Andomar和@ConradFrix下面的註釋）：

SELECT DISTINCT m1.* 
FROM my_table AS m1 
    JOIN my_table AS m2 USING (User) 
WHERE m2.Result = 'Victory' 
    AND m2.Level = 3 

Answer 2

你可以使用一個exists條款，例如：

select * 
from scores s 
where exists 
     (
     select * 
     from scores vl3 
     where vl3.user = s.user 
       and vl3.Result = 'Victory' 
       and vl3.Level >= 3 
     )